New node tunnel issue

Hi all,
I just setup a new mesh node (see: http://www.aredn.org/content/and-running-san-fernando-valley ).

I'm having trouble establishing a tunnel connection with Don Hill. I think the issue might be the same as this post: http://www.aredn.org/content/client-cant-connect-established-servers

I can see traffic going between my node and Don's node, but his side just returns an "ERR" after my side sends the 'CHAL'. 

# vtund -n -f ./vtund.conf KF6NMZ-106-93-246-172-31-148-48 68.5.89.32
vtund[1921]: VTun client ver 3.X 02/26/2017 started
vtund[1921]: Connecting to 68.5.89.32
vtund[1921]: Connection denied by 68.5.89.32
vtund[1921]: Exit

# telnet 68.5.89.32 5525
VTUN server ver 3.X 05/11/2016

My node has a public address, the only firewall is the one running on the mesh node itself.

Something is up with the authentication. Is the "session string" part of the authentication? One of the examples I've seen online has the client named, in my example, "KF6NMZ-106-93-246". This is the string that appears on the 'node status' page. But when I setup vtun, it creates the client strings as "KF6NMZ-106-93-246-172-31-148-48". It appends the subnet to the node name. Is that correct? I manually changed the string to see if it mattered, but it still didn't work.

I copied the vtun config over to another host and ran it with a strace. Here is the output (I changed the CHAL strings):

socket(AF_INET, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(3, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("0.0.0.0")}, 16) = 0
getpid()                                = 21551
writev(2, [{iov_base="KF6NMZ-106-93-246-172-31-148-48 connecting to 68.5.89.32[21551]: Connecting to 68.5.89.32", iov_len=89}, {iov_base="\n", iov_len=1}], 2) = 90
socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 4
connect(4, {sa_family=AF_UNIX, sun_path="/dev/log"}, 110) = 0
sendto(4, "<30>May  2 10:07:07 KF6NMZ-106-93-246-172-31-148-48 connecting to 68.5.89.32[21551]: Connecting to 68.5.89.32", 109, MSG_NOSIGNAL, NULL, 0) = 109
close(4)                                = 0
fcntl(3, F_GETFL)                       = 0x2 (flags O_RDWR)
fcntl(3, F_SETFL, O_RDONLY|O_NONBLOCK)  = 0
connect(3, {sa_family=AF_INET, sin_port=htons(5525), sin_addr=inet_addr("68.5.89.32")}, 16) = -1 EINPROGRESS (Operation now in progress)
select(4, NULL, [3], NULL, {tv_sec=30, tv_usec=0}) = 1 (out [3], left {tv_sec=29, tv_usec=926649})
getsockopt(3, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
fcntl(3, F_SETFL, O_RDWR)               = 0
select(4, [3], NULL, NULL, {tv_sec=60, tv_usec=0}) = 1 (in [3], left {tv_sec=59, tv_usec=923933})
read(3, "VTUN server ver 3.X 05/11/2016\n\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 50) = 50
write(3, "HOST: KF6NMZ-106-93-246-172-31-148-48\n\0\0\0\0\0\0\0\0\0\0\0\0", 50) = 50
select(4, [3], NULL, NULL, {tv_sec=60, tv_usec=0}) = 1 (in [3], left {tv_sec=59, tv_usec=918059})
read(3, "OK CHAL: <xxxxxxxxxxxxxx>\n\0\0\0\0\0\0", 50) = 50
write(3, "CHAL: <xxxxxxxxxxxxxxxxxx>\n\0\0\0\0\0\0\0\0\0", 50) = 50
select(4, [3], NULL, NULL, {tv_sec=60, tv_usec=0}) = 1 (in [3], left {tv_sec=59, tv_usec=922561})
read(3, "ERR\n\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 50) = 50
getpid()                                = 21551
writev(2, [{iov_base="KF6NMZ-106-93-246-172-31-148-48 connecting to 68.5.89.32[21551]: Connection denied by 68.5.89.32", iov_len=96}, {iov_base="\n", iov_len=1}], 2) = 97
socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 4
connect(4, {sa_family=AF_UNIX, sun_path="/dev/log"}, 110) = 0
sendto(4, "<30>May  2 10:07:08 KF6NMZ-106-93-246-172-31-148-48 connecting to 68.5.89.32[21551]: Connection denied by 68.5.89.32", 116, MSG_NOSIGNAL, NULL, 0) = 116
close(4)                                = 0
close(3)                                = 0
getpid()                                = 21551
writev(2, [{iov_base="KF6NMZ-106-93-246-172-31-148-48 connecting to 68.5.89.32[21551]: Exit", iov_len=69}, {iov_base="\n", iov_len=1}], 2) = 70
socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 3
connect(3, {sa_family=AF_UNIX, sun_path="/dev/log"}, 110) = 0
sendto(3, "<30>May  2 10:07:08 KF6NMZ-106-93-246-172-31-148-48 connecting to 68.5.89.32[21551]: Exit", 89, MSG_NOSIGNAL, NULL, 0) = 89
close(3)                                = 0
exit_group(0)                           = ?